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Aneuploidy, an unbalanced karyotype in which one or more chromosomes are present in excess or reduced copy number, causes an array of known phenotypes including proteotoxicity, genomic instability, and slowed proliferation. However, the molecular consequences of aneuploidy are poorly understood and an unbiased investigation into aneuploid cell biology is lacking. We performed high-throughput screens for genes the deletion of which has a synthetic fitness cost in aneuploidy Saccharomyces cerevisiae cells containing single extra chromosomes. This analysis identified genes that, when deleted, decrease the fitness of specific disomic strains as well as those that impair the proliferation of a broad range of aneuploidies. In one case, a chromosome-specific synthetic growth defect could be explained fully by the specific duplication of a single gene on the aneuploid chromosome, highlighting the ability of individual dosage imbalances to cause chromosome-specific phenotypes in aneuploid cells. Deletion of other genes, particularly those involved in protein transport, however, confers synthetic sickness on a broad array of aneuploid strains. Indeed, aneuploid cells, regardless of karyotype, exhibit protein secretion and cell-wall integrity defects. Thus, we were able to use this screen to identify novel cellular consequences of aneuploidy, dependent on both specific chromosome imbalances and caused by many different aneuploid karyotypes. Interestingly, the vast majority of cancer cells are highly aneuploid, so this approach could be of further use in identifying both karyotype-specific and nonspecific stresses exhibited by cancer cells as potential targets for the development of novel cancer therapeutics., (Copyright © 2016 by the Genetics Society of America.)

Successful generation of pentaploid wheat (genome, BBAAD) via interspecific hybridization between tetraploid wheat (BBAA) and hexaploid wheat (BBAADD) holds great promise to mutually exchange desirable traits between the two cultivated wheat species, as well as providing a novel facet for evolutionary studies of polyploid wheat. Taking advantage of the viable and fertile nature of an extracted tetraploid wheat (ETW) with a BBAA genome that is virtually identical with the BBAA component of a hexaploid common wheat, and a synthetic hexaploid wheat, we constructed four pentaploid wheats with several distinct yet complementary features, of which harboring homozygous BBAA subgenomes is a common feature. By using a combined FISH/GISH method that enables diagnosing all individual wheat chromosomes, we precisely karyotyped a larger number of cohorts from the immediate progenies of each of the four pentaploid wheats. We found that the BBAA component of hexaploid common wheat possesses a significantly stronger capacity to buffer and sustain imbalanced D genome chromosomes and appears to harbor more structural chromosome variations than the BBAA genome of tetraploid wheat. We also document that this stronger capacity of the hexaploid BBAA subgenomes behaves as a genetically controlled dominant trait. Our findings bear implications to the known greater than expected level of genetic diversity in, and the remarkable adaptability of, hexaploid common wheat as a staple crop of global significance, as well as in using pentaploidy as intermediates for reciprocal introgression of useful traits between tetraploid and hexaploid wheat cultivars.

Successful generation of pentaploid wheat (genome, BBAAD) via interspecific hybridization between tetraploid wheat (BBAA) and hexaploid wheat (BBAADD) holds great promise to mutually exchange desirable traits between the two cultivated wheat species, as well as providing a novel facet for evolutionary studies of polyploid wheat. Taking advantage of the viable and fertile nature of an extracted tetraploid wheat (ETW) with a BBAA genome that is virtually identical with the BBAA component of a hexaploid common wheat, and a synthetic hexaploid wheat, we constructed four pentaploid wheats with several distinct yet complementary features, of which harboring homozygous BBAA subgenomes is a common feature. By using a combined FISH/GISH method that enables diagnosing all individual wheat chromosomes, we precisely karyotyped a larger number of cohorts from the immediate progenies of each of the four pentaploid wheats. We found that the BBAA component of hexaploid common wheat possesses a significantly stronger capacity to buffer and sustain imbalanced D genome chromosomes and appears to harbor more structural chromosome variations than the BBAA genome of tetraploid wheat. We also document that this stronger capacity of the hexaploid BBAA subgenomes behaves as a genetically controlled dominant trait. Our findings bear implications to the known greater than expected level of genetic diversity in, and the remarkable adaptability of, hexaploid common wheat as a staple crop of global significance, as well as in using pentaploidy as intermediates for reciprocal introgression of useful traits between tetraploid and hexaploid wheat cultivars. [ABSTRACT FROM AUTHOR]